Reinforcing fiber moldings are known, and it is also known that they are used for producing fiber-reinforced plastic (FRP) moldings. A reinforcing fiber molding is formed of a strip-like laminate comprising layered multiple reinforcing fiber sheets and a laminate maintaining material for maintaining the layered state.
The fibers used to form the reinforcing fiber sheets include carbon fibers, glass fibers, aramid fibers, etc.
A known laminate maintaining material is a thermoplastic resin dispersedly deposited in the reinforcing fiber sheets. Stitch yarns for sewing multiple reinforcing fiber sheets together are also known. The reinforcing fiber sheets using any of these laminate maintaining materials is usually called a dry fabric. Further, as a laminate maintaining material, an uncured thermosetting resin impregnated as a matrix into the reinforcing fiber sheets is known, and the reinforcing fiber sheets using the laminate maintaining material is usually called a prepreg.
A reinforcing fiber molding formed of a laminate of dry fabric sheets is usually called a preform. It is known that the preform is impregnated with a flowable resin as a matrix, which is then solidified to produce a fiber-reinforced plastic (FRP) molding.
It is known that in a reinforcing fiber molding formed of a laminate of prepreg sheets, the uncured thermosetting resin in the laminate is cured to produce a fiber-reinforced plastic (FRP) molding.
A reinforcing fiber molding formed of a laminate of dry fabric sheets and having one or more bent portions in the cross sectional form, and a reinforcing fiber molding formed of a laminate of prepreg sheets and having one or more bent portions in the cross-sectional form are known. A fiber-reinforced plastic (FRP) molding having one or more bent portions produced from any of these reinforcing fiber moldings is often used as a structural material of a motor vehicle or aircraft.
A reinforcing fiber molding or a fiber-reinforced plastic (FRP) molding respectively having one bent portion is usually called an L-shaped molding, and a molding having two bent portions is called a C-shaped (U-shaped) or Z-shaped molding. A molding having three bent portions is called a J-shaped molding, and a molding having four bent portions is called an I-shaped (H-shaped) molding.
The invention relates to a method and apparatus for producing a long reinforcing fiber molding which molding has at least two bent portions in the cross sectional form, to have bent surfaces extending in the longitudinal direction.
Methods and apparatuses for producing a long reinforcing fiber molding having at least two bent portions in the cross sectional form, to have bent surfaces extending in the longitudinal direction are disclosed in Patent Literatures 1 and 2.
In the method for producing a reinforcing fiber molding disclosed in Patent Literature 1, as shown in FIG. 5 thereof, in order to form two left and right bent portions in the cross sectional form of an upper strip-like reinforcing fiber sheet 2A (dry fabric), a transforming machine 23 uses a left inner guide roller 35 for forming the left bent portion and a right inner guide roller 35 for forming the right bent portion. However, the left and right inner guide rollers 35 and 35 exist at quite the same positions in the direction for carrying the reinforcing fiber sheet 2A, and the distance between the left inner guide roller 35 and the right inner guide roller 35 in the width direction of the reinforcing fiber sheet 2A is fixed to be constant. That is, the positions of the left inner guide roller 35 and the right inner guide roller 35 in the longitudinal direction of the reinforcing fiber sheet 2A remain the same, and the distance between the left inner guide roller 35 and the right inner guide roller 35 in the width direction of the reinforcing fiber sheet 2A, that is, the gauge remains constant.
Therefore, this production method does not allow the production of a reinforcing fiber molding in which the width of the web portion existing between the two adjacent left and right bent portions changes in the longitudinal direction. For example, a reinforcing fiber molding in which the distance between the flange portion projecting vertically via the left bent portion of the horizontal web portion and the flange portion projecting vertically via the right bent portion of the web portion changes like a taper in the longitudinal direction cannot be produced.
Meanwhile, in the production of a motor vehicle or aircraft, there is a demand for a girder in which the distance between the adjacent bent portions (the width or height of the web portion) changes in the longitudinal direction of a fiber-reinforced plastic (FRP) molding. To meet the demand, as a conventional method, a mold having a desired shape over the entire length in the longitudinal direction in which the distance between the bent portions changes in the longitudinal direction is prepared, and a strip-like laminate comprising reinforcing fiber sheets and a laminate maintaining material is pressed against the mold, to be shaped by the mold, for producing a reinforcing fiber molding. However, this molding method has a disadvantage that the production efficiency is low.
In the method for producing a reinforcing fiber molding disclosed in Patent Literature 2, as shown in FIG. 9 thereof, in order to form two left and right bent portions in the cross sectional form of an upper strip-like reinforcing fiber sheet 260 (prepreg), a hot press device 400 uses an upper mold part 420 for molding the left bent portion and the right bent portion. The upper mold part 420 allows the left bent portion and the right bent portion to be molded simultaneously. That is, at quite the same positions in the direction for carrying the strip-like reinforcing fiber sheet 250 with the distance between both the flange portions, that is, the gauge kept constant, the two bent portions are molded. Therefore, this production method has quite the same disadvantage as that of the reinforcing fiber molding production method disclosed in the abovementioned Patent Literature 1.